[weirdbeard]

I am so close to not being a GM guy anymore! Its my 98 Yukon. It is misfiring and sometimes hard to start when its wet outside. We just had a tropical storm move threw and it has taken its toll on the yukon. I don't get any codes for this problem.
I need ideas.
I keep this thing well tuned. What is the moisture getting to?
Thanks guys.

[Notorious]

Could be a lot of things. Are your plug wires, cap (if used on this engine, I don't know on this) in good shape? How about the seals on critical electrical connections under the hood or elsewhere? However, connection problems on sensors or other vital components would likely throw a code if compromised. Anyhow, a good visual inspection would be a good start. Watch the engine running in the dark and if you see arcing from somewhere in the ignition system, wires, cap, coil(s) that'd be a tip-off.

[Henry Highrise]

Its got to be either your plug wires or your distributer cap...or both.

[weirdbeard]

I just replaced the dist. cap and rotor. I was getting a misfire on cyl. #3. The computer gave me the code. So I inspected the wire on cyl 3 and it was bad. I replaced the whole set with quality wires.
I should add that this morning when I fired it up it died and kind of loped for a second... So I tried again and the same thing happed. I tried again and it started but now it is inconsistently missing and driving me out of my mind! I don't see it being wires for that reason anyway. Why does it not set a code?
This thing is falling apart like a pos and its only nine years old. My 77 c10 runs better!
They don't make um like they used to!

[Notorious]

Not all driveability or other problems will throw a code. How about the plugs themselves? Has the fuel filter been checked and/or replaced in recent history? Engine grounds, fuel pump, pump relay? Especially with modern vehicles, we could guess all day. But a good manual, preferably the factory one, and good, old-fashioned troubleshooting per the manual are sometimes the only way, once the obvious and easier things have been ruled out.

[weirdbeard]

Yeah I replaced everything I could when I bought this truck. Fuel filter, plugs wires, cap rotor, etc etc..
In dry weather it has been running fine. The old fashion trouble shooting is not working for me cuz their are sensors and crap to take into account.
I guess I am just hoping somebody can point me in the right direction.
What could keep the truck from running and or make it misfire when it gets moisture. Thanks.

[Kampr]

I had a vehicle that acted like the transmission was going out. It was still under warrenty so I took it to the dealer. The computer module was getting moisture in it. That probably isn't your problem but you never know with all of the electronics the newer vehicles have.

Danny

[kruzr]

I realize your pain and agony,,very maddenning.
Suggestion: try spraying the electrical connections with a silicone spray or WD 40 to keep moisture out and see what happens ,for 5 bucks you might help trace the glitch...good luck

[tinman386]

Ive had this problem in the past and it was the (ICM) ignition control module. Of course that was on a ford. Other wise here is an idea when you have a dry day and everything is running good take a spray bottle with water to it. Spray one ignition part at a time until it acts up and repair or replace that part.

[tinman386]

Sorry for the double post sight was in a glitch yesterday.

[jimfulco]

My '88 T-bird acted in a similar fashion when the spark plug gaps got out to ~.080". It spat and bucked until it got warm enough to dry itself out, I guess, sometimes taking a mile or two of driving to get right. I gapped them back to .045", and it was happy. I suspect all that elecricity found those old plug wires were easier to jump than that huge gap. Not surprisingly, the wires completely bit the dust a couple of months later.

[weirdbeard]

Hey thanks for all the suggestions guys. I can use all the tips I can get.
Kampr I have been having trans trouble and my truck is at the shop right now getting a new torque converter. I am hoping thats the problem.. I hope my trans trouble is not related to a ECM problem! When I get it back I will start trouble shooting the miss.

[weirdbeard]

Well I started trouble shooting by pulling all plug wires and other electrical harnesses and putting dielectric grease in them. The mis was still there. So I tried the spray bottle of water. I sprayed the area by the coil and module and went for a drive and it was missing like crazy. So I may have it isolated.
I pulled the ignition module and had it tested. It was bad. I bolted on the new one at the store and drove home and the problem was solved. NOT!
This morning my truck is stuttering and sputtering like porky pig!
I would just go ahead and replace the coil but GM thinks its funny to rivet the coil to the motor!
I am no longer a GM man!
What do you guys think dodge or ford?

[carsavvycook]

FORD! They are built tough. Dodge fenders you can push in with your hand. Dodge would be a step down from GM's in my opinion. If you are looking for a 4X4 Ford's have the smoothest ride of these 3. All 3 manufacturer's have their problems, but I have found fewer major problems on Fords, Except their trucks with the 6.0L Diesel. Stay away from that one there's more of them at the dealers for repairs than on the road. I found 786 Tech service bulletins for a 2006 Chevrolet Silverado

Just my opinion!

[79C10]

I had a 1984 plymouth voyager mini van that started missing really bad in the fog or in wet driving , ( road mist ) - My buddy Don told me to spray my plug wires w/ WD-40 . Worked like a charm ....
Give it a shot , it can't hurt nothin.
Good luck with it.